The present invention relates to an apparatus for converting an arbitrary type television signal into a different type television signal, and more particularly to an apparatus for converting an arbitrary type televison signal to a different type television signal to have plural aspect ratios.
Current television systems are different according to nations and regions. These differences are in the number of scanning lines, the aspect ratio of the screen, the scanning method, etc. Further, current television systems have limited resolutions. Accordingly, a television system having a higher resolution than those of current systems is being developed. One recently developed television system having a higher resolution is a high definition television system called "MUSE type (Multiple SubNyquist Sampling Encoding)" which was developed in Japan. The MUSE type has 1125 scanning lines and a screen aspect ratio of 16:9. Thus, the present NTSC type television receiver having 525 scanning lines and a 4:3 screen aspect ratio can not receive the MUSE type television signal. Accordingly, a television signal converter has been required to convert a MUSE type television signal into an NTSC type television signal. This allows reception of the MUSE type television signal by an NTSC type television receiver. The prior art is disclosed in Japanese laid-open Pat. No. Hei 2-291790. In the conventional television signal converter, scanning line conversion, scanning line interpolation, and speed conversion, must be performed twice in order to convert a television signal having a 16:9 aspect ratio and 1125 scanning lines into a television signal having a predetermined aspect ratio different from the 16:9 aspect ratio and say 350 scanning lines. As a result, a long-standing problem in the conventional television signal converter is that the signal process for converting the MUSE type television signal to various NTSC type television signals having different aspect ratios and scanning line numbers is complex. Moreover, the circuit is complicated.